Most conventional cribs have a bedstead made from wood. Although the wood has advantages such as the aroma of logs and great visual aesthetic appeal of traces of growth rings, greater consumption of the wood causes excessive lumbering that is subject to greater restriction as the awareness of environmental protection becomes stronger in the society these days. Thus, the wood becomes more expensive, and the crib bedstead made from wood also is more costly and has environmental protection concern.
As a result, crib bedsteads made of metal have been developed and marketed. The crib bedsteads made of metal tubes are increasingly popular in recent years. They generally are made by coupling and welding metal tubes together. However, welding the metal tubes by soldering is time consuming. Moreover, the metal tubes need to be aligned precisely to avoid inaccurate soldering, thus makes fast assembly difficult. Moreover, the general crib bedstead made of metal tubes, please referring to FIG. 1A, includes a mattress support frame A and a mesh frame A2 that are located at the bottom of a main frame of the crib bedstead coupled with each other by a plurality of springs B. Each spring B includes two hooks B1 that are formed at two ends thereof and latch in an aperture A1 of the mattress support frame A and the mesh frame A2 respectively. The two hooks B1 mostly are formed at a length greater than a diameter of the spring B. Therefore, when a mattress C is placed onto the mattress support frame A the two hooks B1 easily pierce into the mattress C (as shown in FIG. 1B). Moreover, when children jump on the mattress C, due to both the two hooks B1 are formed in a curved shape without inverse hooks, they merely contact with the aperture A1 of the mattress support frame A and the mesh frame A2 at a point respectively. As a result, the two hooks B1 easily escape from the aperture A1 and the mesh frame A2 when subject to jumping under external forces, and fail to securely latch on the inner top surface of the mattress support frame A.